metroid turns 25 this month in japan and 25 next year in the USA. at any rate, nintendo is of course not doing anything for this ocassion.

at any rate, this group of cats is releasing a free double disc of metroid's music remixes. source: http://www.destructoid.com/metroid-turns-25-free-double-disc-remix-album-unlocked-208349.phtml

album website: http://www.shinesparkers.net/harmonyofahunter/

an interesting 5 page retrospective on Metroid & game design
http://www.1up.com/features/the-metroid-legacy

and the Metroid Family Tree (huge image)
http://www.1up.com/media/03/9/1/5/lg/082.jpg